The proposed research will extend work currently in progress supported by NIH Grant AM-10956. Studies of biologic function of neutrophil leukocytes will investigate the role of microfilaments in mediating endocytosis and the mechanism of fusion of lysosomal granules with phagocytic vacuoles. These biologic activities will be evaluated in leukocytes ingesting microspheres with varying size and surface properties through modification of the process by cytochalasins that block filament action and ionospheres that alter cytoplasmic levels of calcium and other cations. Studies of lysosomes in macrophages and mast cells will concern localization of lysozyme, of certain cations and of previously unrecognized peptidases in organelles of these cells. The role of cell surface components including immune complex receptors of phagocytic activity will be investigated by appraising cell surfaces for such receptors and other glycoproteins and evaluating the affect of ionophore and other probes on such staining. Cytochemical investigation of epithelial cell activities mediating transport of electrolytes will be continued by undertaking ultrastructural localization of electrolytes and complex carbohydrates in secretions and on the cell surface. Epithelial cell activity in defense against microbial invasion will be studied by immunostaining for lysozyme and immunoglobulin. Interest will continue also in the development of new methods for cytochemical differentiation of carbohydrate-rich components at the light and electron microscopic level. Certain aspects of these inquiries into normal cell function will be applied to investigation of pathogenesis of lesions in cystic fibrosis paying particular attention of the involved cell in this disease and delineation of the abnormal intracellular organelle and altered cell function.